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Application of the method of removal of space debris objects by an ion beam - the IBS method - seems to be the most effective for cleaning the GEO region. This is due to the low energy consumption for transfer one object in a safe orbit delta-V≃11 m/s and the possibility of removal several objects by one spacecraft. The service spacecraft for this purpose can be developed on the basis of telsat technology, taking into account its functions. Such a spacecraft should contain an ion beam injector to act on the removed object and an electric propulsion system, which serves to compensate for the ion injector thrust and to control the spacecraft motion both during transportation of the removed object and during interorbital flights. The development of a weakly diverging ion beam injector, determination of the composition and structure of an electric propulsion system, ballistics of the optimal sequence of interorbital flights, and development of an algorithm for controlling a virtual cluster: spacecraft-removed object are discussed in the article. In the majority of works on IBS, commercial ion thrusters are considered as an ion injector and engines. However, ion beams from ion thrusters have a half angle of divergence of 120-150. When propagating in outer space, the ion beam expands irresistibly due to electron thermal effects. As a result, the distance at which the spacecraft must follow the removed object during its transportation for effective impulse transmission to it should be small (estimated, about 7 m). Taking into account the dimensions of both objects and the uncontrolled movement of the removed object relative to its center of mass, the object transportation operation carries noticeable risks. The results of an experimental study of a prototype of an ion injector with an initial half angle of divergence of 20-40 are presented. The use of such an injector would provide a distance between objects of 15–20 m and reduce the risk of their collision. In connection with IBS, various aspects of spacecraft control during transportation of an object with one, two or more engines as part of the electric propulsion system are considered. In the conceptual design of the spacecraft presented in this work, the electric propulsion system contains two stationary plasma thrusters, each of which is mounted with the possibility of independent rotation respect to two mutually perpendicular directions. Spacecraft motion control, including thrust vector control, is carried out by means of the thrusters coordinated rotation. The characteristics of the spacecraft and its subsystems intended for the removal of several objects are conceptually considered. For example, parameters of the mission for the removal of up to 10 objects from the NORAD catalog from the GEO region are given. In the future, using the result obtained, the control of SC of this scheme when IBS implementing in the low-Earth orbit will be considered.

In this paper, the effect of the chemical composition of .22LR bullets was studied and correlated to the extent and quality of the markings left after shooting them with the same gun. Scanning electron microscopy and optical comparator microscopy equipped with 3D and profilometry modules were used as non destructive techniques with two main purposes. The first is to assist the firearm examiner in the choice of the ammunition most suitable for preparing the test bullets. The second is to propose an approach, crossing data from optical microscopy, profilometry and space-resolved chemical analysis, for explaining the morphology of striae, whether continuous or interrupted. Among the most notable results is the finding that commercial .22LR ammunition show very wide interbrand, interlot and intralot variability. A selection of test ammunition solely based on the same brand and model used on the crime scene is therefore not suitable, urging the need for a more accurate choice, based on a preliminary chemical analysis.

This paper proposes a cost-effective, compact, noncontacting optoelectronic targeting system for measuring the distribution of projectile motion. The major elements of this system include a light emitting diode (LED) array, photodiode detecting array, double-layered aperture arrays, adaptive threshold circuit, and date acquisition. Through cooperating with double-layered aperture arrays, the system effectively reduces the radiation width of the light source to the photodiode detecting surface, and filters out the influence of incident light from the adjacent apertures on both sides above each photodiode to the corresponding photodiode detecting surface. It realizes that the response of the photodiode array corresponds to the coordinates of the light screen one by one. Through the sensitivity analysis of the light screen of the system, the system detecting threshold when the projectile passes through the light screen is calculated, and the corresponding adaptive threshold circuit is designed to prevent misjudgment when the system works. The measuring error of the system can reach &plusmn, 2 mm by experimental verification. Compared with other projectile&rsquo, s distribution measuring systems, the proposed system has the advantages of having high precision, convenient debugging, is nondestructive, and is a noncontact system.

A mathematical model is developed to characterize the progressive time-evolution of a fragmenting incandescent object. The objective of these models is to provide a spatio-thermal footprint of the fragmentation field, which can be useful to guide fire safety rules in manufacturing workplaces, as well as to estimate fire hazards. Ascertaining the time-evolution of the temperature of the fragments is quite difficult to measure experimentally, which motivates the model development. Initially, analytical models based solely on ballistics, which provide qualitative trends, are developed to provide insight into the fundamental ratios that govern safe operating conditions. Thereafter, rapid numerical spatio-thermal models, which provide quantitative information, are then developed, based on particle methods. The model uses the released energy from the initial blast pulse to provide the starting kinetic energy of the system of particles and then numerically computes the trajectory and thermal state of the fragments under the influence of Numerical examples and provided and extensions to high-fidelity are discussed.

Gun violence is a global phenomenon with regional variation in frequency and severity. Handguns are often used in violent deaths such as suicides and homicides. Hence, ballistic trauma is a critical subject of forensic investigations. Trauma patterns are fundamental evidence for the reconstruction of the incident and the determination of the manner of death. This study investigated the differences in trauma patterns with a series of experiments using six different calibers (.22 LR, .38 Special, .380 ACP, 9 x 19 mm, .40 S&W, and .45 ACP) and four different bullet types. Synbone® spheres (polyurethane bone proxies) were used for close range (30 cm) simulated executions. The polyurethane spheres constitute an excellent proxy for human crania at the macroscopic level as suggested by other studies. The results showed that the radius of the entrance wound is positively correlated (Pearson’s correlation coefficient R=0.846, p

This study evaluates and compares the accuracies of five different ballistic models in predicting the speed profile of a supersonic bullet using radar measured speed data for 36 types of bullets. Each of the five ballistic models is parameterised by a ballistic constant and the muzzle speed of the bullet. In practice, each of these two parameters spans a wide range of values because of the large number of different bullet types that are available for use in a variety of applications. For a given bullet type, the bullet's ballistic constant and muzzle speed are determined by fitting the ballistic model to the data in a least-squares (LS) sense, and the root-mean-square (RMS) and maximum absolute (MA) deviations of the LS fit of the model from the data are computed. The best ballistic model (out of the five) is the one that has the smallest RMS and MA errors for the maximum number of bullet types. This ballistic model has been applied to accurate ranging of small arms fire using a single sensor node, with and without a priori knowledge of the model parameters, and its effectiveness for both cases is demonstrated using real data recorded from a field experiment.

As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT) ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

The objective of this study was to investigate the terminal ballistics of police shootings in which the bullets went through any motor vehicle structure before fatally wounding the occupants. 6 cases that occurred in Porto district between 1998 and 2013 were studied. The firearms used were 7.65 mm (n = 1) or 9 mm (n = 3) calibre semi-automatic pistols and 9 mm calibre submachine guns (n = 2); the bullets were full metal jacket type. The metal jacket of the collected projectiles was totally or partially destroyed in 3 cases. It exhibited a deformed structure in all cases. The trajectories of the bullets in the vehicles were always more or less linear, even when initial impact was at an oblique angle. The entry holes in the victims' bodies were larger or much larger in size than the calibre of the bullets. They were located, with the exception of one of the cases, in the left half of the body. The trajectories in the victims' bodies were from front to back, in one case, and from back to front in all others. Exit wounds were only found in two cases. Death occurred immediately after the victim was shot only in one case, despite a vital structure has been hit in all cases. The cases studied support the idea that the use of firearms against vehicles with the sole intention of immobilisation entails uncontrollable danger to the lives of the occupants, and especially when done by police forces not specifically trained for that purpose. Therefore, such use of firearms should be avoided.

A laboratory gun that uses compressed gas as its propellant was designed and tested for the study of small projectiles traveling in soils with initial velocities ranging from 50 to 200 m/s. The gun employed the use of air or helium with an electrically triggered, pneumatically piloted, solenoid valve. The triggering system was designed to provide remote activation. A photo gate speedometer was utilized to measure the exit velocity of each projectile. Details of the electro-pneumatic control system are presented in this paper along with the design of the gun assembly and its subsystems. The effects of different design parameters, including muzzle length, projectile mass, propellant type, and volume of compressed gas utilized, on projectile velocity were investigated. Statistical analysis of the gun performance is presented. The gun is currently being used to visualize the fundamental physics of rapid earth penetration in soils, using transparent soils.

We study the transient indirect effect of a rifle bullet on bone in the gelatin-bone composite target experimentally and computationally. The process of a 56 type 7.62-mm rifle bullet penetrating the composite target has been simulated using numerical method. The experiment provided the criteria for verifying the correctness of the numerical model. We have obtained tomographic data of bone by CT scans, and also defined the bone as different layers by the gray scale to simulate its heterogeneity. The computed results are in good agreement with the experimental data. Effects of the impact velocity and bone location on damage caused to the composite target have also been studied. The numerical results imply the follows: When the velocity of bullet increases, the stress on bone also increases with the earlier pressure peak; When the bone is located in a certain distance from the trajectory, it will not be fractured, although it is affected by the stress wave.

Instead of the capillary plasma generator (CPG), a discharge rod plasma generator (DRPG) is used in the 30 mm electrothermal-chemical (ETC) gun to improve the ignition uniformity of the solid propellant. An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun (2D-IB-SPETCG) is presented to describe the process of the ETC launch. Both calculated pressure and projectile muzzle velocity accord well with the experimental results. The feasibility of the 2D-IB-SPETCG model is proved. Depending on the experimental data and initial parameters, detailed distribution of the ballistics parameters can be simulated. With the distribution of pressure and temperature of the gas phase and the propellant, the influence of plasma during the ignition process can be analyzed. Because of the radial flowing plasma, the propellant in the area of the DRPG is ignited within 0.01 ms, while all propellant in the chamber is ignited within 0.09 ms. The radial ignition delay time is much less than the axial delay time. During the ignition process, the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech. The radial ignition uniformity is proved. The temperature of the gas increases from several thousand K (conventional ignition) to several ten thousand K (plasma ignition). Compare the distribution of the density and temperature of the gas, we know that low density and high temperature gas appears near the exits of the DRPG, while high density and low temperature gas appears at the wall near the breech. The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch. The 2D-IB-SPETC model can be used for prediction and improvement of experiments.

Objective To evaluate the learnability and feasibility of a new technique comprising a needle-guidance-system (NGS) for ultrasound-assisted lumbar puncture. Method Using a randomized crossover study design, 24 medical students were asked to perform an ultrasound-assisted lumbar puncture on a gel phantom using two different techniques that each included a paramedian insertion site. Procedure 1 (P1) used a pre-procedural ultrasound scan to predetermine the ideal insertion point. Procedure 2 (P2) applied a new technique comprising an NGS for performing real-time ultrasound-guided lumbar puncture. Success rates and performance times for both procedures were compared. Participants were also asked to complete a post-study questionnaire, both to quantitatively assess the workload involved and state their personal preferences. Results In comparison to the pre-procedural scan (P1), the NGS (P2) was associated with a significant increase in the number of successful punctures per participant (5 (P2) [interquartile range: 3.3–5.0] vs. 3 (P1) [interquartile range: 1.3–4.0], p = 0.005), and led to a significant reduction in performance time (118 seconds vs. 80.6 seconds, p < 0.001). In terms of workload perception, NGS use was associated with significantly better performances and lower frustration levels, as rated by students in the post-study questionnaire. Finally, 23/24 participants stated their preference for P2. Conclusion Our newly-developed technique for real-time ultrasound-guided lumbar puncture proved to be learnable and feasible for novices, and only required a small amount of training. The use of an NGS therefore has the potential to serve as a key feature of the ultrasound-assisted lumbar puncture.

The number of head wounds due to firearms remains low in France because these cases are primarily linked to suicide (or attempted suicide) and, to a lesser extent, to attacks or hunting accidents [1]. Characterized by the impact of a projectile, which in most cases is made of metal, at high levels of kinetic energy, such acts generally result in severe trans-cerebral lesions with significant levels of morbidity/mortality [2]. Seldom are cases reported in the literature that give a detailed study of intracranial foreign bodies made of bone in such situations [3]. Here we report on the case of two suicides resulting from a transcranial gunshot wounds caused by weapons and ammunition issued by the French police force. Each case helped distinguish a characteristic bone fragment, in the form of a "patch", equivalent in size to the caliber of the bullet.

High-speed videos of blood spatter due to a gunshot taken by the Ames Laboratory Midwest Forensics Resource Center (MFRC) [1] are analyzed. The videos used in this analysis were focused on a variety of targets hit by a bullet which caused either forward, backward, or both types of blood spatter. The analysis process utilized particle image velocimetry (PIV) and particle analysis software to measure drop velocities as well as the distributions of the number of droplets and their respective side view area. The results of this analysis revealed that the maximal velocity in the forward spatter can be about 47±5m/s and for the backward spatter - about 24±8m/s. Moreover, our measurements indicate that the number of droplets produced is larger in forward spatter than it is in backward spatter. In the forward and backward spatter the droplet area in the side-view images is approximately the same. The upper angles of the close-to-cone domain in which droplets are issued in forward and backward spatter are, 27±9° and 57±7°, respectively, whereas the lower angles of the close-to-cone domain are 28±12° and 30±18°, respectively. The inclination angle of the bullet as it penetrates the target is seen to play a large role in the directional preference of the spattered blood. Also, muzzle gases, bullet impact angle, as well as the aerodynamic wake of the bullet are seen to greatly influence the flight of the droplets. The intent of this investigation is to provide a quantitative basis for current and future research on bloodstain pattern analysis (BPA) of either forward or backward blood spatter due to a gunshot.

Since common energetic materials are not easily compatible with existing additive manufacturing techniques, the Energetic Materials department of TNO in the Netherlands worked closely together with the Additive Manufacturing and Material Solutions groups of TNO to develop new types of energetic material that can be processed in standard 3D printers, aiming at better performance and greater flexibility in the manufacturing of energetic products. This contribution gives an overview of potential applications for additive manufacturing of energetic materials, ranging from rocket propellants to explosives, gun propellants, and other applications. The paper then briefly describes TNO’s research efforts since 2013 into AM of energetic materials. Next, the work performed on additive manufacturing of gun propellants, using stereolithography, is described in more detail, including the results of the material development and characterization, and performance test results, including test firings with a 30 mm gun. The paper concludes with an overview of the current status of the research at TNO, as well as a definition of the next steps to be taken and a vision of the future of additive manufacturing of energetic materials.

The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

The aim of this paper is to determine the velocity, energy, maximum range and distance at which pellets fired from an air rifle of kinetic energy below 17 J can pose a threat to unprotected human skin. Doppler radar equipment and exterior ballistics software were used in this examination.

A large body of evidence demonstrates that resistance training has been ineffective for improving walking outcomes in adults with neurological conditions. However, evidence suggests that previous studies have not aligned resistance exercise prescription to muscle function when walking. The main aim of this study was to determine whether a training seminar for clinicians could improve knowledge of gait and align resistance exercise prescription to the biomechanics of gait and muscle function for walking. A training seminar was conducted at 12 rehabilitation facilities with 178 clinicians. Current practice, knowledge and barriers to exercise were assessed by observation and questionnaire prior to and immediately after the seminar, and at three-month follow-up. Additionally, post-seminar support and mentoring was randomly provided to half of the rehabilitation facilities using a cluster randomised controlled trial (RCT) design. The seminar led to significant improvements in clinician knowledge of the biomechanics of gait and resistance training, the amount of ballistic (t = -2.38; p = .04) and conventional (t = -2.30; p = .04) resistance training being prescribed. However, ongoing post-seminar support and mentoring was not associated with any additional benefits F(1, 9) = .05, p = .83, partial eta squared = .01. Further, improved exercise prescription occurred in the absence of any change to perceived barriers. The training seminar led to significant improvements in the time spent in ballistic and conventional resistance training. There was no further benefit obtained from the additional post-seminar support. The seminar led to improved knowledge and significantly greater time spent prescribing task-specific resistance exercises.

We present an attitude estimation method for self-guided ballistic munitions from onboard magnetometers. An adaptive feedback filter is used to remove actuator-induced magnetic disturbances whose spectrum overlaps the signal of interest. A state-augmented extended Kalman filter (EKF) is used to estimate roll rate and sensor bias from the filtered data. Experimental results demonstrate that this method is able to accurately estimate the roll without phase delay inherent in other methods.

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, a NIST/ATF joint project entitled National Ballistics Imaging Comparison (NBIC) was initialized in 2008. The NBIC project aims to establish a National Traceability and Quality System for ballistics identifications in crime laboratories within the National Integrated Ballistics Information Network (NIBIN) of the U.S. NIST Standard Reference Material (SRM) 2460 bullets and 2461 cartridge cases are used as reference standards. 19 ballistics examiners from 13 U.S. crime laboratories participated in this project. They each performed 24 periodic image acquisitions and correlations of the SRM bullets and cartridge cases over the course of a year, but one examiner only participated in Phase 1 tests of SRM cartridge case. The correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed Quality System and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard.

In this paper, a new proportional-navigation guidance law, called retro-proportional-navigation, is proposed. The guidance law is designed to intercept targets that are of higher speeds than the interceptor. This is a typical scenario in a ballistic target interception. The capture region analysis for both proportional-navigation and retro-proportional-navigation guidance laws are presented. The study shows that, at the cost of a higher intercept time, the retro-proportional-navigation guidance law demands lower terminal lateral acceleration than proportional navigation and can intercept high-velocity targets from many initial conditions that the classical proportional navigation cannot. Also, the capture region with the retro-proportional-navigation guidance law is shown to be larger compared with the classical proportional-navigation guidance law.

Radar is assumed to be tracking a cannon launched projectile travelling in a 2 dimensional drag environment. Extended Kalman Filter (EKF) is explored for the estimation of position and velocity of the projectile. Simulation is carried out using MATLAB and the results are presented. Finally, based on the results, EKF is recommended for tracking the projectile.

In the first part of the paper [Naik D, Sankaran S, Mobasher B, Rajan SD, Pereira M. Development of reliable modeling methodologies for fan blade-out containment analysis. Part I: experimental studies. Int J Impact Eng, in press], details of the experiments to characterize the behavior of dry fabrics including Kevlar®49, and ballistic tests involving the fabric were presented. In this second part of the paper, we discuss the development and verification of a constitutive model for dry fabrics for use in an explicit finite element program. The developed constitutive model is implemented as a user-defined subroutine in LS-DYNA, a commercial finite element program. It is then used to simulate a suite of ballistic tests [Naik D, Sankaran S, Mobasher B, Rajan SD, Pereira M. Development of reliable modeling methodologies for fan blade-out containment analysis. Part I: experimental studies. Int J Impact Eng, in press] that replicate conditions seen in an engine fan blade out (FBO) event. A qualitative and quantitative comparison of the deformation shape of the fabric containment system and a quantitative comparison of the absorbed energy are carried out. Results indicate that the developed constitutive model provides a very encouraging start in modeling these high-speed events and could provide as Federal Aviation Administration (FAA) desires, an attractive complement to full-scale engine FBO tests.

The present paper constructs a rigid–plastic model to assess the effect of a soft nose on the perforation of metallic plates struck by a stubby projectile. A low-density nose-cabin-column, i.e., an assembly of seeker and guidance/control unit, is installed in the front of a real missile. It usually acts as an energy absorber and buffer in the perforation of metallic plates and notably affects the terminal results of projectile. The problem is equivalent to a blunt rigid projectile with a soft nose perforating a circular metallic plate. Effects of transverse shear, bending and membrane deformations on the perforation process are included in a rigid–plastic analysis. Especially the effect of an ahead structural response, induced by the soft nose impacting the target plate, is considered in the model. Analytical formulae for the ballistic performance are obtained for a range of plate thicknesses, which agree well with available experimental results.

This study evaluates the energy absorption, perforation and damage evolution created by cylindrical projectile of different nose geometries in woven roving mat/epoxy laminates with 0.45� orientation. A series of ballistic impact tests have been carried out on the laminate with projectile nose geometries representing hemispherical, conical, and conical with round nose and truncated tip. A gas gun projectile launcher set-up was employed to impact the target at different speeds. The damage pattern, perforation mechanism and ballistic limit for each type of projectiles have been studied. Truncated-nose projectile shows the highest ballistic limit while sharp-nose shows the lowest. A quasi-static punch test was carried out on targets with projectiles of above-mentioned nose geometries to assess the damage evolution at a constant strain rate. The maximum load required to cause perforation during punch test was noted for hemispherical-nose projectile. An in-depth layerwise analysis was carried out to analyse the damage in each layer. Copyright � 2008 Taylor & Francis.

Helmet designs have evolved over the last three millennia and the use of helmet may be as old as warfare itself. In 600 B.C. the Greeks in Sparta crafted single-piece helmet from bronze, which provided complete head protection, leaving only narrow slits in front for vision and for ventilation. Later in 250 B.C. the Romans developed several helmet designs, which included the round legionary's helmet and the gladiator's helmet, with broad brim and pierced visor, providing exceptional head, face and neck protection. The use of helmets in battle fields continued until the end of 13th century, which signaled a radical change in the emphasis on head protection. With the invention of gunpowder and the growing effectiveness of firearms over swords and spears, helmets gradually vanished from the battle scenes. The metal helmet that once protected against sword and arrows offers little protection against musket rounds. The United States Civil War provides an excellent illustration—in war soldiers donned cloth hats and caps, with little or no emphasis on head protection. In World War I, the helmet was reintroduced because it protected the head against metal-fragments of exploding artillery shells and indirect fire. The French, owing to General Adrian, were the first to adopt the helmet as standard equipment in early 1915. The British, the Germans, and then the rest of Europe soon followed. In World War I, the German helmet provided the best protection for soldiers. It was manufactured in at least two sizes, and different head contours were accommodated by an adjustable leather lining, which provided comfort and allowed for ventilation. The typical helmet used during that period was a hardened steel shell with an inner liner and weighed about 0.5–1.8 kg. Since then, helmets have been issued to troops in all military conflicts, marking the beginning of the development of modern military helmet. This paper presents the results from experiments and AUTODYN-3D® simulations on the ballistic impact of a KEVLAR® helmet. In the experiment, spherical projectile (~11.9 g), launched from a light gas gun, strikes the helmet with an impact velocity of 205 m/s. The interaction of the projectile with the KEVLAR® helmet is captured using high-speed photography. This helmet-projectile interaction is compared with that obtained from the AUTODYN-3D® simulation. Post-test damage photos from the experiments are also compared with those from the simulations. The response of the helmet from the simulations is consistent with those from the experiments. Also included in this paper are AUTODYN-3D® simulations on two ballistics test standards for KEVLAR® helmets. They are namely the NIJ-STD-0106.01 Type II and the V50 requirement of the US military specification for Personal Armor System Ground Troops (PASGT) Helmet, MIL-H-44099A. For the simulation on MIL-H-44099A, a fragment-simulating projectile (FSP) strikes the helmet with an impact velocity of 610 m/s. The simulation revealed that an impact velocity above 610 m/s is required to perforate the KEVLAR® helmet. For the simulation on NIJ-STD-0106.01 Type II helmet, the projectile is a 9 mm full-jacketed bullet with a striking velocity of 358 m/s. Results from the simulation show that the KEVLAR® helmet is able to defeat a 9 mm full-jacketed bullet traveling at 358 m/s.

Internal ballistics simulations of solid rocket motors have been conducted with the propellant grain's 3-D burning surface geometry described by a new minimum distance function approach and the internal flowfield represented by 1-D, time-dependent, single-phase compressible flow equations. The combustion model includes erosive burning and unsteady, dynamic burning corresponding to transient energy storage in the heated surface layer of the propellant. The integrated internal ballistics code (Rocballist) is used to investigate the role of these two burning rate augmenting mechanisms in solid rocket motor performance. Two tactical motors are used as test cases. Results indicate that dynamic burning can be the dominant factor in producing a short-duration ignition pressure spike in low-L* motors, particularly if the L/D ratio is not too large and the port cross section is nonrestrictive (e.g., center perforated grain). However, when L/D is large and the port cross section is noncircular in the aft section (aft fins/slots), erosive burning can take over in dominating the burning rate to the extent that an otherwise progressive pressure-time trace becomes regressive/neutral. That is, erosive burning can effectively prolong the initial pressure spike in some star-aft motors. The results also show that with sufficiently accurate models of dynamic burning and erosive burning, it is reasonable to expect reliable internal ballistics predictions with suitable simplified flowfield models, thereby realizing significant reductions in computation time compared with 3-D, multiphase reacting flow simulations.

The aim of this work is to develop a methodology for the evaluation of the ballistic requirements of a helicopter component. The situation studied in the work refers to the possibility of a damaged helicopter performing an emergency manoeuvre and a 30-min return flight after the impact of a 7.62 NATO projectile on a shaft of the tail rotor transmission. The paper describes the finite element methodology adopted to simulate the impact of the projectile on the shaft, and outlines the hypotheses on which this methodology is based. The numerical simulation of the propagation of the crack originating from the damage caused by the impact is also described. It is thus possible to determine the time required to reach failure of the shaft. The effect of the residual stresses on the residual life of the shaft is studied in detail.

Woven fabrics are widely used in soft body armour. The ballistic performance of a range of narrow fabrics was determined and compared to that of wider fabric panels. In contrast to conventional ballistic fabrics, it was found that the performance of narrow fabrics was highly sensitive to changes in fabric specification. Furthermore, it was shown that square weave fabrics may not necessarily be superior to unbalanced fabrics in narrow fabric form. It was also confirmed that narrow fabrics absorb more energy than wider fabric panels when undergoing direct ballistic impact, particularly when gripped in a two-sided configuration. Ways were sought of utilising these improvements in performance when the narrow fabrics are brought together to make full-width armour panels. Potentially, the observed improvements in performance could have been offset by the lines of weakness between adjacent fabric strips or by the weight of the structure required to grip on two sides. However, after investigating a number of potential solutions, significant improvements in the performance-to-weight ratios over simple fabric armour were achieved using an assembly of narrow fabrics attached to a lightweight composite frame.

A research program was funded by the European space agency (ESA) to improve and optimize the shields used to protect the manned elements of the international space station (ISS) against impacts of micro-meteoroids and orbital debris. After a review of existing shielding systems and after a series of light gas gun (LGG) experiments to screen interesting new materials and configurations, the research focused on shields with a metallic outer bumper, an intermediate stuffing and an inner metallic wall (representing the pressure shell of a manned spacecraft). Additional LGG experiments were performed on several configurations, with bumpers containing aluminum foam or made from titanium and aluminum super-alloys and with several combinations of stuffing materials. The comparison of the test results showed that ceramic cloth (Nextel) plus aramid fabric (both 2D and 2.5D Kevlar weaving) used as intermediate bumper gave a good protection compared to the overall area density requested. Configurations with by-layered aluminum foam bumpers (sandwich panels with asymmetric Al face sheets and a core made from Al foam) and Kevlar stuffing showed excellent resistance to normal impacts at about 6.5 km/s. However, the influence of material properties varying from batch to batch and threshold phenomena made ranking among the tested options rather difficult. The test campaign showed that it was rather difficult to improve over the already good ballistic performances of the debris shields developed by Alenia Spazio for the ISS manned elements. The by-layered Al-foam bumper and Kevlar stuffing configuration was selected for additional tests, including low velocity and oblique impacts, to develop ballistic limit curves.

Currently, optical devices, such as microscopes and CCD cameras, are utilized for identification of bullets and tool marks in the field of forensic science. While these optical methods are easily manageable and effective, they are under great influence of illumination condition. In other words, appearances of striations through these optical devices have possibility to be changed by lighting condition. Besides these appearance-based approaches, we can utilize three dimensional (3D) geometric data of tool marks that are free from lighting condition. In this study, we focused on 3D geometric data of landmark impressions on fired bullets for identification. We obtained the 3D surface data of tool marks by a confocal microscope and reconstructed virtual impressions on a PC monitor from the geometric data. Furthermore, the 3D data are exploited to numerical matching of two surface shapes. We also visualized the difference of two shapes. In order to do this, two surface models are aligned automatically. In this process, pairings of correspondent points on both surfaces are determined. Distance analysis between these pairs leads to a shape comparison. Since comparison results are visualized, they are intuitive and easily perceptive.

An improved procedure for modeling the operation of a light-gas gun is proposed. The motion of working bodies in both the firing chamber and the light-gas chamber is studied within the framework of the mechanics of heterogeneous media. The problem of barrel heating taking into account its melting and removal of thermal ablation products into the medium inside the bore is solved in a coupled formulation. Heat and mass transfer and friction on the barrel surface are calculated using empirical dependences. The deformable piston is considered compressible and elastoviscoplastic. Allowance is made for the presence of a clearance between the lateral surface of the piston and the barrel bore walls and the associated gas flow between the firing and the light-gas chamber. Calculation results are given.

The physical and chemical phenomena involved in the ballistic process, both in conventional guns and in electrothermal-chemical (ETC) guns, are very complex, so that optimization of gun performance requires a detailed understanding of the influence of different parameters. The initial stage of propellant ignition is critical to the rest of the process, in terms of both performance (muzzle velocity, repeatability) and safety. A better understanding of the ignition stage is thus very important in achieving improved performance. In this paper, we propose a new method and ignition sensor aimed at providing direct experimental information about the propellant ignition process. We further report on measurements of the ignition delays, and the propagation of the "ignition wave", performed using these sensors in experimental devices such as closed bombs and gun simulators.

The deviation of bullets passing through window pane glass of a thickness of 6 mm was investigated for varying angles of incidence. Projectiles of calibre 0.22 and 0.38 (wadcutter) were used. The 0.22 bullets break into multiple pieces, resulting in a large distribution of exit angles. An increasing deviation of 0.38 wadcutter projectiles was seen for increasing angles of incidence. For incident angles larger than 35°, an unexpected ricochet was noticed. This phenomenon is of importance when examining crime scenes. A number of parameters which have to be taken into account for further experiments is suggested.

In recent years, great strides have been made regarding the identification of the dominant loads that cause beam type vibrations of cannons during ballistic operation. These motions infringe upon shot accuracy because at projectile disengagement, the muzzle's kinematic state may compromise the projectile's intended flight path. This is particularly relevant to coil gun loading, which, unlike gas launch, applies the recoil load to the muzzle end of the barrel instead of the breech. This effectively places the barrel in a state of columnar compression during the launch cycle that may exacerbate structural vibrations known as gun "whip".

The Sandia Hypervelocity Launcher (HVL) uses impact techniques on a two-stage light-gas gun to launch flier plates to velocities in excess of 10 km/s. An important problem in designing successful third stage techniques for impact launching fliers to such velocities is detailed understanding of the interior ballistic performance of the third stage. This is crucial for preventing melt and fracture of the flier plates during the extraordinary accelerations that they undergo (accelerations on the order of 10{sup 9} g are typical on the HVL). We seek to optimize HVL launch conditions in order to achieve two major goals: first, to maximize the potential launch velocity for a given flier, and second, to allow different flier configurations. One tool that we can apply in studying HVL performance is the use of multi-dimensional wave propagation codes. We have used such codes, particularly the Sandia Eulerian code CTH, to study a variety of interior ballistics issues related to gun performance and launcher development for almost ten years. Recently this work has culminated in a major contribution to HVL design, namely the capability to launch ``chunk`` fliers. `Me initial phases of design development were solely devoted to CTH computations that studied potential designs, identifiedmore » problems, and posed possible solutions for launching chunk fliers on the HVL. Our computations sufficiently narrowed the design space to the point that systematic experimental progress was possible. Our first experiment resulted in the successful launch of an intact 0.33 gram titanium alloy chunk flier to a velocity of 10.2 km/s. The thickness to diameter ratio of this flier was approximately 0.5.« less

Herein, we study the technique of improving the gun performance by installing a diaphragm in the pump tube of the gun. A CFD study is carried out for the 0.28 in. gun in the Hypervelocity Free Flight Radiation (HFF RAD) range at the NASA Ames Research Center. The normal, full-length pump tube is studied as well as two pump tubes of reduced length (approximately 75% and approximately 33% of the normal length). Significant improvements in performance are calculated to be gained for the reduced length pump tubes upon the addition of the diaphragm. These improvements are identified as reductions in maximum pressures in the pump tube and at the projectile base of approximately 20%, while maintaining the projectile muzzle velocity or as increases in muzzle velocity of approximately 0.5 km/sec while not increasing the maximum pressures in the gun. Also, it is found that both guns with reduced pump tube length (with diaphragms) could maintain the performance of gun with the full length pump tube without diaphragms, whereas the guns with reduced pump tube lengths without diaphragms could not. A five-shot experimental investigation of the pump tube diaphragm technique is carried out for the gun with a pump tube length of 75% normal. The CFD predictions of increased muzzle velocity are borne out by the experimental data. Modest, but useful muzzle velocity increases (2.5 - 6%) are obtained upon the installation of a diaphragm, compared to a benchmark shot without a diaphragm.

In 1998, A Baseball Traveled From A Minor-League Baseball Practice Area Into An Adjacent Parking Lot, Ultimately Striking A Six-Week Old Infant Being Placed Into A Car Seat. The Issue Of Appropriate Fence Heights Was Raised By The Infant Family. The Forensic Engineering Analysis Included Analysis Of The Baseball Flight Dynamics, The Application Of Statistical Analysis And The Design Of Sports Facilities. During Discovery, Prior Knowledge Of Similar Baseball Flight Paths Was Brought To Light, Presenting Challenges To The Defense.

A novel miniaturised system for measurement of the in-flight characteristics of an arrow is introduced in this paper. The system allows the user to measure in-flight parameters such as the arrow's speed, kinetic energy and momentum, arrow drag and vibrations of the arrow shaft. The system consists of electronics, namely a three axis accelerometer, shock switch, microcontroller and EEPROM memory embedded in the arrow tip. The system also includes a docking station for download and processing of in-flight ballistic data from the tip to provide the measured values. With this system, a user can evaluate and optimize their archery equipment setup based on measured ballistic values. Recent test results taken at NIST show the accuracy of the launch velocities to be within +/− 0.59%, when compared with NIST's most accurate ballistic chronograph.

In the design and development of solid propellant rocket motors, the use of numerical tools able to predict the behavior of a given motor is particularly important in order to decrease the planning times and costs. This paper is devoted to present the results of the internal ballistics numerical simulation of the NAWC tactical motor n. 6, from ignition to burn-out, by means of a quasi-one-dimensional unsteady numerical simulation model, SPINBALL, coupled with a three-dimensional grain burnback model, GREG. In particular, the attention is focused on the effects on the SRM behavior of the erosive burning, total pressure drops and the cause of the pressure overpeak occurring during the last part of the ignition transient. The final objective is to develop an analysis/simulation capability of SRM internal ballistics for the entire combustion time with simplified physical models, in order to have reduced the computational costs, but ensuring an accuracy greater than the one usually given by zero-dimensional models. The results of the simulations indicate a very good agreement with the experimental data, as no attempt of submodels calibration is made, enforcing the ability of the proposed approach to predict the SRMs internal flow-field conditions. The numerical simulations show that NAWC n. 6 internal ballistics is completely led by the erosive burning, that is the root cause of the pressure peak occurring immediately after the SRM start-up.

This paper presents the tests and analytical approach used on the development of a steel riser cutter for the CEV Parachute Assembly System (CPAS) used on the Orion crew module. Figure 1 shows the riser cutter and the steel riser bundle which consists of six individual cables. Due to the highly compressed schedule, initial unavailability of the riser material and the Orion Forward Bay mechanical constraints, JSC primarily relied on a combination of internal ballistics analysis and LS-DYNA simulation for this project. Various one dimensional internal ballistics codes that use standard equation of state and conservation of energy have commonly used in the development of CAD devices for initial first order estimates and as an enhancement to the test program. While these codes are very accurate for propellant performance prediction, they usually lack a fully defined kinematic model for dynamic predictions. A simple piston device can easily and accurately be modeled using an equation of motion. However, the accuracy of analytical models is greatly reduced on more complicated devices with complex external loads, nonlinear trajectories or unique unlocking features. A 3D finite element model of CAD device with all critical features included can vastly improve the analytical ballistic predictions when it is used as a supplement to the ballistic code. During this project, LS-DYNA structural 3D model was used to predict the riser resisting load that was needed for the ballistic code. A Lagrangian model with eroding elements shown in Figure 2 was used for the blade, steel riser and the anvil. The riser material failure strain was fine tuned by matching the dent depth on the anvil with the actual test data. LS-DYNA model was also utilized to optimize the blade tip design for the most efficient cut. In parallel, the propellant type and the amount were determined by using CADPROG internal ballistics code. Initial test results showed a good match with LS-DYNA and CADPROG simulations. Final paper will present a detailed roadmap from initial ballistic modeling and LS-DYNA simulation to the performance testing. Blade shape optimization study will also be presented.

This paper describes the design of the single entry tunneler (SET), devised to create a loop-shaped path in forearm subcutaneous tissue prior to placement of a vascular graft for hemodialysis access. Existing tunnelers are almost universally rigid and require high forces and multiple incisions to complete even the most simple path geometries. Furthermore, they are guided from the handle with limited tip-location feedback. This paper presents a three-stage tunneler design consisting of concentric nested tubes. The first stage is a straight stainless steel tube; the second is a smaller pre-curved nitinol tube and the third is a straight inner nitinol tube. By deploying the stages in this order, SET is able to produce an approximately180 ◦ looped path in tissue. A tip that is illuminated via a fiber optic cable provides visual feedback of the tip location. The SET outer diameter is limited to ensure that the pre-curved nitinol will not exceed its yield strain and not require an excessive force to be deployed from the straight outer stage. Therefore, a custom dilator was designed to increase the size of the tunnel to one suitable for the intended graft. A prototype of the SET tunneler and dilator system was manufactured. The device was shown to achieve the desired path in ballistics gel and was capable of at least 100 repeated-use cycles. By reducing the number of required incisions and improving ease of use during graft insertion procedures, the SET has the potential to greatly reduce the risk of infection and degree of unnecessary tissue trauma while increasing tunneling accuracy.

A dual-density Rodman cone, with 1/d=7, has been found to be attractive for electromagnetic launch and may have adequate terminal ballistic performance. Stable flight is achieved from the correct distribution of mass within the projectile body. The design provides some flexibility for the armature in that all the armature mass is used for aerodynamic stability. Furthermore, the acceleration can be supported by a simple one-piece armature. A bore rider, which is less than 10% of the total mass, is needed for in-bore stability and structural support at the tungsten/aluminum interface. Work to date has focused on small-caliber applications, but substantial gains can be achieved when the bore size is increased to cannon caliber. General design principles for a mass stabilized projectile are presented. Nearly all aspects of launch, flight, and terminal effects as a function of bore size are addressed. Flight and terminal effects are computed from curve fits to existing experimental data. >

A railgun for the study of the interaction of meteorites with planetary surfaces and the interaction of space debris was developed. The authors have attained a velocity constantly higher than 5 km/s, with a maximum of 6 km/s. The importance of plasma confinement behind the projectile to prevent a leakage is shown to realize a high velocity. An effective acceleration using an aluminum rail is also shown. >

We have studied the high-frequency behavior and the ultimate limiting factor to the cutoff frequency for the Datta–Das spin transistor using device Monte Carlo simulations. We have found that the maximum frequency of operation is not related to intrinsic parameters to the spin of the carriers, such as the Larmor frequency or the spin lifetime, but to the transit time through the channel.

The muzzle imprint (barrel mark) is a pressure abrasion typically associated with contact shots. Apart from the contours of the actual muzzle profile, other constructional parts such as the front sight and/or the recoil spring guide of semiautomatic pistols may be imprinted next to the bullet entrance wound. In some types of submachine guns the shoulder stock can be folded forward so that its end partly encircles the muzzle. If such a weapon was in contact with the skin at the instant of discharge, a corresponding contusion mark is to be expected. The imprint configuration may point to the type of weapon and to the way in which the gun had been held when firing the shot. The paper presents the injury pattern in a 36-year-old man who committed suicide with a Scorpion SA Vz 61 submachine gun cal. 7.65mm Browning from former Czechoslovakia.

In forensic science, automated firearms identification is an important and yet unsolved problem. On the way to the solution, one of the most important phases is data acquisition. To be able to identify firearms in a reliable way, all the striated and impressed marks on metallic surfaces of cartridge cases should be visible. But two-dimensional images of cartridge cases are very sensitive to the type and direction of the light source(s). Depending on illumination conditions, the images of marks change drastically and sometimes they simply disappear. But, if the three-dimensional (31)) topography of the surface is obtained, the geometry of the marks, which is independent of the illumination, is available. Thus, by providing illumination independent features that can be used for automated matching, 3D data have the potential to make automated matching much reliable. In the literature on data acquisition for automated firearms identification, a few different ways of three-dimensional surface extraction are described, like laser interferometry or laser profilometry. This Study presents a real life application of another method, photometric stereo, for the acquisition of 3D topographic data for cartridge cases, which is the one used in BALISTIKA Ballistics Image Analysis and Recognition System. In order to construct 3D topographic data, first of all, two-dimensional images were acquired using a specially designed set-up. After the images were calibrated radiometrically, photometric stereo method was applied. In order to minimize the low-frequency errors in the final surface, a surface-fitting algorithm was used. The method uses low-cost equipment and image acquisition is not time-consuming. Results were compared to interferometric measurement values for error assessment. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

This paper describes a research program conducted to enable accurate prediction of the impact tolerance of the shuttle Orbiter leading-edge wing panels using 'physics-based- codes such as LS-DYNA, a nonlinear, explicit transient dynamic finite element code. The shuttle leading-edge panels are constructed of Reinforced-Carbon-Carbon (RCC) composite material, which issued because of its thermal properties to protect the shuttle during re-entry into the Earth's atmosphere. Accurate predictions of impact damage from insulating foam and other debris strikes that occur during launch required materials characterization of expected debris, including strain-rate effects. First, analytical models of individual foam and RCC materials were validated. Next, analytical models of individual foam cylinders impacting 6-in. x 6-in. RCC flat plates were developed and validated. LS-DYNA pre-test models of the RCC flat plate specimens established the impact velocity of the test for three damage levels: no-detectable damage, non-destructive evaluation (NDE) detectable damage, or visible damage such as a through crack or hole. Finally, the threshold of impact damage for RCC on representative Orbiter wing panels was predicted for both a small through crack and for NDE-detectable damage.

To investigate micro-Doppler signatures of precession for a warhead with empennages, the model of precession is built and mathematical formulas of a micro-Doppler induced by different scattering centres are derived. The relationship between the micro-Doppler appearing frequency of empennages and micro-motion frequencies is first acquired, then two important precession features, namely coning frequency and spinning frequency, are extracted based on the micro-Doppler. Simulation results are provided to demonstrate the validity of the proposed method.

A nonlinear missile guidance controller with Thrust Vector Control (TVC) inputs for the interception of a theater ballistic missile is presented. In this paper, the midcourse phase of the missile is investigated, during which many non-ideal conditions must be considered, such as variation of the inertia of the missile and existence of the aerodynamic force, and an effect controller is designed to take into account the properties of TVC. Specifically, a 3 DOF optimal midcourse guidance law is designed to minimize the control effort and the distance between the missile and the target. The asymptotic stability of the overall system is proved by Lyapunov theory. Extensive simulations are conducted to validate the effectiveness of the proposed guidance law for TVC.